Question: $ { {-2} \times \left[\begin{array}{rrr}{-2} & {2} & {1} \\ {1} & {2} & {1}\end{array}\right] = {?} } $
Answer: To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rrr}{-2}\times{-2} & {-2}\times{2} & {-2}\times{1} \\ {-2}\times{1} & {-2}\times{2} & {-2}\times{1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{4} & {-4} & {-2} \\ {-2} & {-4} & {-2}\end{array}\right]}$